Lipopolysaccharides (LPS) are proinflammation mediators that can induce the inflammatory model of the hippocampal neuron, and neuroinflammation participates in the pathophysiology of depression. Xiaoyao Pill is a classical Chinese medicine formula that has been used for the treatment of mental disorders such as depression in China since the Song dynasty. We established a hippocampal neuronal cell inflammation model by LPS and investigate the intervention effect and mechanism of Xiaoyao Pills. The expression levels of IL-6, TNF-α, IDO, 5-HT, brain-derived neurotrophic factor, and β-nerve growth factor were detected by enzyme-linked immunosorbent assay. mRNA levels of IL-6, TNF-α, 5-HT1A, IDO-1, brain-derived neurotrophic factor, nerve growth factor, tropomyosin receptor kinase B, tropomyosin receptor kinase A, and cAMP response element-binding protein were detected by reverse transcription-polymerase chain reaction. To further validate, protein expression was determined by western blot and immunofluorescence. Lipopolysaccharide-induced neuroinflammatory state resulted in the release of IL-6, TNF-α, and IDO and a decrease of BDNF, NGF, TrkB, TrkA, CREB, p-CREB, p-CREB/CREB, and SYP and inhibited hippocampal neurogenesis in the hippocampal neuron. Xiaoyao Pills significantly decreased the levels of IL-6, TNF-α, and IDO in cell supernatant and increased the expression of BDNF, NGF, TrkB, TrkA, CREB, p-CREB, p-CREB/CREB, and SYP as well as the average optical density of BrdU/NeuN double-labelled positive cells. Our study shows that lipopolysaccharides induce inflammation and nerve damage in hippocampal neurons, which are closely related to the pathological mechanism of depression. Xiaoyao Pills (XYW) play an important neuroprotective effect, which is related to its inhibition of neuronal inflammation and promoting the recovery of nerve injury. These results provide a pharmacologic basis for the treatment of depression of XYW in clinical application.

Lipopolysaccharides are pro-inflammation mediators that can induce inflammation in the serum, hippocampus, and cortex of animals. And lipopolysaccharide-induced neuroinflammatory state resulted in significant depression-like behaviors, including reduced locomotor activity in the open field test, reduced saccharin preference, added immobility time in tail suspension test and forced swimming test, decreased comb time in the splash test, and increased latency to food in the novelty suppressed feeding test time, and reduced the levels of neurotrophic factors and synaptic proteins, and decreased Nissl bodies. Treatment with Xiaoyao Pills ameliorated the depression-like behavior, decreased the levels of inflammatory indicators, increased those of neurotrophic factors and synaptic proteins, and restored Nissl bodies. Our study suggests that lipopolysaccharides induce inflammation and nerve injury, thereby leading to depression. Xiaoyao Pills could be considered a potential therapeutic candidate for inflammation-induced depression.

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The Jing-Fang powder n-butanol extract (JFNE) has antiinflammatory properties; however, its active ingredient remains unknown. In addition, the mechanism by which JFNE exerts its anti-inflammatory effects on lipopolysaccharide (LPS)-induced inflammation in RAW264.7 cells is yet to be explored. In this study, JFNE was isolated by chromatography to obtain fraction D. We found that pretreatment of LPS-induced RAW264.7 cells with JFNE and fraction D for 3 hours significantly reduced the levels of nitric oxide (NO), interleukin (IL)-1b, and tumor necrosis factor-a (TNF-a) in the supernatant of cell cultures, and fraction D could also reduce the level of IL-6. In addition, JFNE and fraction D significantly reduced the mRNA expression of inducible NO synthase (iNOS), IL-6, IL-1b, and TNF-a. JFNE and fraction D significantly inhibited the phosphorylation of proteins and mRNA expression levels of phosphoinositide 3-kinase (PI3K) and protein kinase B (PKB/AKT). Moreover, JFNE and fraction D significantly decreased the mRNA expression of iNOS, v-rel reticuloendotheliosis viral oncogene homolog A (RELA), and nuclear factor of k light polypeptide gene enhancer in B cells 1 (NF-kB1), whereas an increase in the mRNA expression of conserved helix-loop-helix ubiquitous kinase (CHUK) was observed. In addition, JFNE and fraction D downregulated the protein expression of iNOS, nuclear factor-kB (NF-kB) (p50), and phosphorylated NF-kB (p65). These results show that JFNE and its isolated fraction D exert specific antiinflammation properties in LPS-stimulated RAW264.7 cells that are regulated by inhibition of the PI3K/Akt and NF-kB signaling pathways.